The San Francisco Giants and St. Louis Cardinals, the two teams that simply refuse to die in this postseason, meet in Game 6 of the NLCS on Sunday night in a series that appropriately now appears destined to go the full seven games.

"Can you explain it?" Giants outfielder Hunter Pence asked a reporter after the 5-0 Game 5 win. "I don't think you can explain it. But I hope you guys enjoy the games as much as we love to play 'em."

Indeed, the series has been entertaining—and not only for baseball fans. The Detroit Tigers, who are killing time between series by scrimmaging against their instructional league squad, have to love the prospect of the Giants and Cardinals burning their No. 1 starters in a potential Game 7 on Monday night.

But before there can be talk of Game 7, there must be a Game 6. And at this point, it makes more sense to focus on each team’s cons than its pros. So here goes:

THREE CONCERNS FOR THE CARDINALS

Carlos Beltran’s knee. That he was able to start Game 5 after missing Game 4 because of a sore left knee was a good sign. And stealing second base in the first inning Friday was an even better sign. But Beltran’s knee problems have been an issue all season and will remain an issue for the duration of the postseason. While all might be fine one day—thanks in large part to multiple hours of pregame therapy—there could be discomfort the next. It’s that unpredictable, and the Cardinals can’t afford to be without such a productive bat.

Ryan Vogelsong. The Giants’ Game 6 starter clearly is past his late-August/early September struggles. Vogelsong went 2-0 with a 0.53 ERA in his final three regular season starts, threw five innings of one-run ball in his lone NLDS start and held the Cardinals to one run in seven innings in Game 2 of the NLCS. He also shut out St. Louis for seven innings at Busch Stadium in August. In Game 6 he will be back at AT&T Park, where his ERA was a full run lower (2.86) than on the road (3.87).

The cleanup hitter. Allen Craig hit .307 with 22 homers and 92 RBIs in 119 regular-season games and .348 (8-for-23) with a homer and four RBIs in the Wild Card and NLDS rounds. However, he is 2-for-16 and RBI-less in the first five games of the NLCS. A World Series hero last postseason, Craig will be a key factor in determining whether St. Louis plays in the Fall Classic for a second consecutive year.

THREE CONCERNS FOR THE GIANTS

AT&T Park. So much for any home-field advantage. San Francisco has played four games at AT&T Park this postseason and won just one of them. Meanwhile, St. Louis won its Wild Card Game in Atlanta and its NLDS clincher in Washington, D.C. Overall, the Cardinals are 4-2 on the road in these playoffs. And in 16 postseason games in the NL this month, the home teams are 5-11. That gives the Tigers, who will begin the World Series in an NL park on Wednesday, even more reason to smile.

Chris Carpenter. Yes, the Giants knocked him around (five runs on six hits and two walks) and knocked him out (he lasted only four innings) in Game 2 of this series. And, yes, he has struggled at times in what really amounts to spring training for him, since he didn’t make his season debut until Sept. 21. But Carpenter can take it to another level in elimination games. He won the decisive Game 5 of the NLDS in Philadelphia last postseason and then won Game 7 of the World Series. A opportunity like this is exactly why he pushed himself so hard to return from “season-ending” surgery in July.

The cleanup hitter. NL MVP candidate Buster Posey is just 3-for-18 with five strikeouts in this series and still is searching for his first RBI. (For the record, Barry Zito has more RBIs than Posey in the NLCS.) Posey is 0-for-4 with runners in scoring position in the NLCS, a number that must improve for San Francisco to advance. With No. 3 hitter Pablo Sandoval heating up, perhaps Posey will begin to see better pitches.